Plug devices



Nov. 10, 1964 ,-w s 3,156,373

I PLUG DEVICES Filed May 28, 1962 2 Sheets-Sheet 1 INVENTOR. LEONARDEWILLIS ATTORNEYS Nov. 10, 1964 F. WILLIS 3,156,373

PLUG DEVICES Filed May 28, 1962 2 Sheets-Sheet 2 All VENTOB. Leona EWIHis PTTG RNKPIS United States Patent 3,156,373 PLUG DEVICES Leonard F. Willis, Birmingham, Mich., assignor to Han Le Ray Corporation, Madison Heights, Mich., a corporation of Michigan Filed May 28, 1962, Ser. No. 200,018 Claims. (Cl. 220-245) This application is a continuation-in-part of my now abandoned application Serial No. 54,158, filed Sept. 6, 1960 for Safety Plugs.

My invention relates to plug devices and more particularly to a plug adapted for insertion in tubular passages such as the breech end of the bore of a gun barrel to prevent insertion of a cartridge in the bore.

Various devices for this purpose have been devised heretofore, such as the expansible device shown and described in Patent No. 2,836,918, issued to S. Pula et al., but such devices have various defects that my invention has overcome.

Foremost is the fact that heretofore such devices have been made to fit only a single size of tubular passage. Another problem is that only a single peripheral area of the plug is arranged to engage the passage wall.

Heretofore also, such plugs have not been easy to install or remove, nor have they been such as can be easily and cheaply manufactured.

An object of my invention is to facilitate the plugging of tubular passages such as gun barrels when not in use by providing a simplified plug element readily used for a variety of different sizes of such tubular passages.

Another object of the invention is to improve plugs for tubular passages by constructing a plug having both ends readily expansible for locking engagement in passages of different sizes.

A further object of the invention is to simplify the manufacture and use of plugs for tubular passages by providing an improved expansible one piece plug carrying readily operated expander means at both ends.

For a more complete understanding of these and other objects of the invention, reference may be had to the accompanying drawings illustrating preferred embodiments of the invention in which like reference characters refer to like parts throughout the several views and in which FIG. 1 is a longitudinal fragmentary cross-sectional view of a tubular passage such as a gun barrel with the plug shown in elevation.

FIG. 2 is an end view as seen substantially from the line 2-2 of FIG. 1. 7

FIG. 3-is a cross-sectional view taken substantially on i the line 3-3 of FIG. 1.

FIG. 4 is a longitudinal cross-sectional view of a gun barrel breech end with the plug also in cross-section.

FIG. 5 is a cross-sectional view like FIG. 4 but with a barrel of a larger bore-size, and

FIG. 6 is a side elevational view of the present plug device expanded as it is when used in the barrel of FIG. 5. FIG. 7 is a longitudinal fragmentary cross-sectional View of another preferred embodiment of the present invention, prior to expansion of the plug.

FIG. 8 is an end view seen from the right side of FIG. 7.

FIG. 9 is an end view seen from the left side of FIG. 7, and

FIG. 10 is a fragmentary view of structure shown in FIG. 7 but enlarged for purposes of clarity.

A plug 10 is illustrated in FIGS. 14 as adapted to fit within the end of the bore 11 of a tubular member 12. The plug 10 is substantially cylindrical and is made of any suitable resilient material such as nylon. One end 3,156,373 Patented Nov. 10, 1964 of the plug is provided with a flange 13 which preferably has a portion missing as at 13A. The gap 13A is provided so that the plug 10 may be used to plug the breech end of a firearm and is positioned so that the cartridge ejector mechanism (not shown) of the gun will not be able to engage the flange 13, which could otherwise damage the plug 10. It is apparent that to plug other types of tubular passages the flange 13 may be provided without the gap 13A.

A plurality of spaced radially extending slots 14 are cut into one end of the plug 10 as shown, and a second set of similar slots 15 are cut into the other end. The slots 14 and 15 are angularly offset with respect to each other and all extend longitudinally about of the length of the plug so that the inner ends overlap for approximately /2 of their longitudinal dimension.

An axial hole or bore 16 extends through the plug 10 and has a normally substantially straight smooth medial portion 16A terminating at one end in an outwardly diverging frusto-conical portion 16B and at the opposite end in an outwardly diverging frusto-conical portion 16C.

The slots 14 and 15 are preferably made as cross-cuts in the respective plug ends, and thus provide at both ends a plurality of segment portions 10A and 10B respectively.

A flat head socket cap screw 20 extends through the bore 16 as illustrated, and is provided with a head 20A having an included angle the same as the included angle of the bore portion 16B in which it is adapted to seat. A frusto-conical nut element 21 is tap threaded to receive the screw 2% and has an included angle the same as the included angle of the bore portion 160 in which it is adapted to seat.

The included angle of the nut 21 and of the bore portion 16C must be less than the included angle of the screw head 20A and of the bore portion 16B for a reason which will later appear. For best operation, the maximum angle the outer edge of the nut 21 and the bore portion 16C for with respect to the axis of the plug is preferably between and degrees as seen at A in FIG. 4, and the maximum angle the edge of the bolt head 20A and bore portion 168 form with respect to the plug axis is preferably between 35 and degrees as seen at B in FIG. 4.

The head of the screw 20 has a socket 22 or any other means desired by which a tool (not shown) may be engaged with the screw for rotating same.

In operation, the plug 10 may be inserted as shown in FIGS. l-4 into the bore 11 which in these illustrations is the minimum size bore for the plug. The flange 13 engages the end of the tubular member 12. The tool is inserted in the head of the screw 20 and rotated. It will be found that the plug 10 will remain stationary both because of peripheral friction, and even if this is not enough, for example, if a clearance exists between bore and plug, the pressure inward will cause the flange 13 tomake frictional contact with the tubular member 12. If desired, the under side of the flange 13 may be scored or roughened to increase friction.

The nut 21, although inaccessible within the bore 11, will not rotate because the wedge angle with which it engages the conical recess or bore portion 160 is less than 16 in the bore 11. In effect, the screw head 20A and the nut element 21 constitute wedges operable when urged toward one another to respectively displace the expansible ends of the plug 10 radially outwardly with the inner element being operative first because of the smaller wedge angle.

In FIGS. and 6, the same plug and included screw 20 andnut 21 are shown as used in a tubular member 112 having a larger borelll. It will be seen that the ends of the plug 10 can be outwardly displaced in the same way as described above to lock the plug 10 Within the bore 111. Since the slots 14 and 15 extend for a considerable length and even through the medial plug bore portion 16A, the segments 10A and 10B are capable of a very large radial deflection, so that the same plug 10 may be used for a great variety of bore sizes, eliminating the necessity of having a different plug for each different size tubular member a person might wish to plug. Also, there is no need for dealers to stock a large variety of plugs.

Moreover, since both ends of the plug are expansible, more positive locking is assured. With the outer end also expanded, no space is available around the periphery for the insertion of knife blade, screw driver, or other commonly available tools which might otherwise be used in an attempt by a child to dislodge the plug. In addition, peripheral contact assumes sealing against entry of foreign matter.

It will be apparent that in removing the plug by turning the screw 21 the screw head 29A will loosen before the nut 21, due to the above described ditference in wedge angle. Then, since pressure by the tool on the screw is inward, as soon as the screw head A loosens, the nut will be readily forced outwardly of its seat.

It should be noted that the wedge angle of the nut cannot be too small or approach a critical wedge angle. Otherwise it will tend to lock or jam within the plug bore 16. Yet the angles of both nut 21 and screw 20A must not be too great, otherwise too great a torque on the screw 20 would be required for effective operation.

FIGS. 7-10 illustrate another preferred embodiment of the present invention as comprising a substantially cylindrical plug 110 provided with a flange 113 which may be substantially similar to the described flange 13 or may be provided on a smaller peripheral portion of the plug 110 as illustrated in FIGS. 8 and 9.

Spaced radially extending slots 114 and 115 are provided and are positioned as slots 14 and 15 heretofore described. An axial bore 116 extends through the plug 110 and is provided with a reduced end portion 116A. The plug 110 is internally threaded at 1168 as can best be seen in FIGS. 7 and 10. The bore 116 is provided with an outwardly diverging frusto-conical section 116C at the end opposite the reduced end portion 116A.

The slots 114 and 115 divide the plug into segmented portions 110A and 1MB at each end.

A fiat head socket cap screw 120 substantially similar to screw 20 of FIGS. 1-6 extends through the bore 116 and is carried in the threaded portion 116B. A head portion 129A of the screw 120 has an included angle the same as the included angle of the bore portion 116C is seated therein as shown. The head of the screw 120 has a socket 122 or any other means by which a tool (not shown) may be engaged with the screw 120 for rotation thereof.

As can best be seen in FIG. 10, the thread angle A of the screw 120 and the thread angle B of the threaded portion 1163 are preferably degrees forming an angle C of 60 with respect to the axis of the plug 110. The angle D formed by the head portion 120A of the screw 120 and the bore portion 116C with respect to the axis of the plug 119 is preferably about 41 unlike the embodiment described above, is less than the wedge angle formed at the opposite end of the plug; i.e. in this modification by the thread angles A and B. Thus ordinarily the segments A would be displaced outwardly first. However to insure that the segments 110B are displaced outwardly upon initial rotation of the screw 120, the slots are made somewhat longer than the slots 114. This produces a greater flexibility at the inner end of the plug 119 and causes that end to engage the walls of the bore 111 first. It is apparent that if it is desired that the segments 110A engage the walls of the bore 111 first, then the slots 114 and 115 will be made of the same length.

In operation the plug 110 is inserted into the bore 111 of a tubular member 112 and a tool is inserted in the head of the screw and rotated. Because the slots 115 are longer than the slots 114 initial rotation of the screw 120 will cause the threads 118 to coact with the threaded portion 116A of the plug bore 116 to produce radially outward pressures as illustrated by the arrows in FIG. 10. These pressures in combination with the slots 115 will cause the segments 110B to be displaced radially outwardly as shown in the dotted line position to engage the walls of the bore 111. Further rotation of the screw 120 will cause head portion 120A to cam the bore portion 116C to move the segments 110A radially outwardly to engage the walls of the bore 111. Thus the plug 110 is effectively locked in the bore 111 at both ends.

In the preferred embodiment illustrated in FIGS. 7- 10 the sides of threaded portion 118 of the screw 120 constitute wedges which when the screw is rotated radially displace the segments 110A. The screw head 120A also is a wedge and because it is of a smaller wedge angle it would ordinarily move the segments 110A outwardly upon initial rotation of the screw 120. The slots 115 being longer than the slots 114, however, cause the segments 110A to move radially outwardly only after the segments 1103 have engaged the wall of the bore 111.

It will be noted that without the slots in the plug, the function would not be the same, but instead, the plug would tend to be deformed by compressive pressure and bulge in the center.

It is apparent that the above described plugs are especially suitable as a safety device for plugging the breech end of gun barrels and thus preventing the insertion of a cartridge while at the same time preventing dust and other foreign matter from entering the barrel. However, since these devices may be used to plug other types of tubular members, it is not intended that this invention be limited to firearm plugs.

Although I have described only two embodiments of my invention, it will be apparent to anyone skilled in the art to which the invention pertains that various other changes and modifications may be made therein without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A device for plugging the open end of a tubular passage and the like comprising (a) an elongated plug adapted for insertion in said tubular passage,

(12) said plug being provided with radial slots extending longitudinally inwardly from both ends to provide an inner arcuate end segment and an outer arcuate end segment,

(0) a screw carried in said plug,

(d) means carried by said plug and operable to radially displace said arcuate end segments radially outwardly into binding engagement with the inner surface defining said tubular passage upon rotation of said screw;

(e) said means being further operable to urge said inner end segment into binding engagement with said surface before urging said outer end segment into binding engagement with said surface upon rotation of said screw.

2. A device for plugging the open end of a tubular passage and the like comprising (a) an elongated plug adapted for insertion in said tubular passage,

(15) said plug being provided with radial slots extending longitudinally inwardly from both ends to prvide an inner arcuate end segment and an outer arcuate end segment,

(c) a screw carried in said plug,

(d) means carried by said plug and operable to radially displace said arcuate end segments radially outwardly into binding engagement with the inner surface defining said tubular passage upon rotation of said screw;

(e) said radial slots provided in said inner end segment being longer than said radial slots being provided in said outer end segment whereby said inner end segment is more flexible than said outer end segment and upon rotation of said screw said inner end segment will be urged into binding engagement with said inner surface before said outer end segment is urged into binding engagement with said surface.

3. A device for plugging the open end of a tubular passage and the like comprising (a) an elongated plug adapted for insertion in said tubular passage,

(b) saidplug being provided with radial slots extending longitudinally inwardly from both ends to provide an inner arcuate end segment and an outer arcuate end segment,

(0) a screw carriedin said plug,

(d) an inwardly sloped frusto conical recess being provided in said inner end of said plug,

(2) a Wedge member being carried in said recess and being operable upon being moved axially inwardly to displace the arcuate segments provided at said inner end radially outwardly into binding engagement with the inner surface defining said tubular passage,

(1) an inwardly sloped frusto conical recess being provided in said outer end of said plug,

(g) said screw being provided with a frusto conical head portion seated in said outer end recess whereby upon axially inward movement of said screw said head portion displaces the arcuate segments provided at said outer end radially outwardly into binding engagement with said surface,

(It) said wedge member being threaded to receive said screw whereby rotation of said screw produces relative axial movement of said head portion and said wedge member,

(i) the angle formed by said inner end recess with respect to the axis of said plug being greater than the angle formed by said outer end recess with respect to the axis of said plug whereby upon tightening said screw said wedge member will be moved axially inwardly before said head portion will be moved axially inwardly and upon loosening said screw said head portion will be moved axially outwardly before said wedge member moves axially outwardly.

4. The device as defined in claim 3 and in which said first mentioned angle is between 35 and degrees and said second mentioned angle is between 30 and 45 degrees.

5. A device for plugging the open end of a tubular passage and the like comprising (a) an elongated plug adapted for insertion in said tubular passage,

(b) said plug being provided with radial slots extending longitudinally inwardly from both ends to provide an inner arcuate end segment and an outer arcuate end segment,

(c) said plug having an axially extending frusto conical recess provided in said outer end and an axial, threaded bore extending from said recess to said inner end,

(d) a screw having a threaded shank portion carried in said threaded bore and having a conical head portion carried in said recess,

(e) said radial slots at said inner end being longer than said radial slots at said outer end whereby upon initial tightening said screw said threaded shank portion will engage said threaded bore and cam said inner end radially outwardly into binding engagement with the inner surface defining said tubular passage and upon further tightening of said screw said head portion will urge said outer end radially outwardly into binding engagement with said surface.

References Cited in the file of this patent UNITED STATES PATENTS 945,403 Mohun Jan. 4, 1910 2,046,224 Vanderhoof June 30, 1936 2,494,899 Ross Jan. 17, 1950 3,054,427 Bonnette Sept. 18, 1962 

1. A DEVICE FOR PLUGGING THE OPEN END OF A TUBULAR PASSAGE AND THE LIKE COMPRISING (A) AN ELONGATED PLUG ADAPTED FOR INSERTION IN SAID TUBULAR PASSAGE, (B) SAID PLUG BEING PROVIDED WITH RADIAL SLOTS EXTENDING LONGITUDINALLY INWARDLY FROM BOTH ENDS TO PROVIDE AN INNER ARCUATE END SEGMENT AND AN OUTER ARCUATE END SEGMENT, (C) A SCREW CARRIED IN SAID PLUG, (D) MEANS CARRIED BY SAID PLUG AND OPERABLE TO RADIALLY DISPLACE SAID ARCUATE END SEGMENTS RADIALLY OUTWARDLY INTO BINDING ENGAGEMENT WITH THE INNER SURFACE DEFIN- 